good luck getting an answer on this forum. i don't know where to go for answers but have you noticed the number of post that are seen but not answered? quite a few of them. maybe theres another forum somewhere to get answers that i'm not aware of.
As you may have already found out, Logitech Illuminated keyboard doesn't work with this board when booting. In OS everything works fine.
I have the same keyboard and had to get another one to get into bios. Effed up I know, but apparently the Illuminated keyboard does this on other motherboards as well.
its not the motherboard its the bios! I rolled back the bios and it now works fine!? I would LOVE to be able to use the newest bios though
Looks like this subject has been dead for a couple of years, but at any rate:
I have the same keyboard and the same problem. However, when I did an internet search on this problem, it seems to be a problem with lots of USB keyboards and lots of motherboards. So it doesn't appear to be only an Intel or Logitech issue.
I may try rolling back the bios, but it didn't work under the old bios either.
Are you using the latest (5599) BIOS for the DX58SO? That's the version I'm running on my DX58SO with a Logitech MK520 keyboard/mouse, and all is well. True, this is a wireless combo with the USB unifying receiver plugged into one of the front USB ports, so perhaps that makes a difference.